Conductor



Feb. 16, 1943. c. E. SWARTZ CONDUCTOR Filed March 15, 1939 an"IIII'IIIII'II Fig.5

. INVENTOR. CARL E. 5 WARTZ ATTORNEY.

Fig.4

Patented Feb. 16, 1943 2,311,138 .con uqroa Carl E. Swartz, Cleveland,Ohio, assignmto The Cleveland Graphite Bronze Company, Cleveland, Ohio,a corporation of Ohio Application March 15, 1939, Serial No. 262,070

12 Claims. The present invention relating, as indicated,

to conductors is more particularly directed to a hollow tube orconductor for the transmission of alternating electrical currents inwhich the conductor is characterized by a comparatively lower cost ofproduction, greater convenience and economy in shipment from factory toinstallation point, greater strength, lower corona discharge and highcapacity for carrying alternating current. Briefly stated, my inventionconsists of a composite strip of two metals integrally bonded togetherinto a strip formed into a suitable crosssectional shape and one inwhich the inner metal is of relatively strong material such as a ferrousmetal or alloy and the outer metal is of relatively high conductivitymetal such as copper or aluminum.

To the accomplishment of the foregoing and related ends, said inventionthen consists of the means hereinafter fully described and particularlypointed out in the claims, the annexed drawing and the followingdescription setting forth in detail a certain structure embodying theinvention, such disclosed means constituting, however, but one ofvarious-structural forms in which the principle of the invention may beused.

In said annexed drawing: Fig. 1 is a transverse section through one formof my improved conductor;

Fig. 7 is a view in perspective of another form of my conductor; and

Fig. 8 is a view'similar to Fig. 1, but showing the edges of the formedconductor welded to each other.

In the transmission of alternating currents. it

has long been known that in conductors used for this purpose, the outersurface of the conductor carries the larger portion of the energy andthe inner portion is effective mainly in its ability to reinforce,strengthen and support the outer current carrying layer. Many designs ofconductors have been devised to take advantage of these conditions,among which the more common and commercially used are steel cored solidwire cable having a copper or aluminum outer layer and steel coredstranded copper or aluminum cable. Another type of conductor consists ofa hollow copper tube in which relatively flat segments are engaged alongtheir edges with others to form a hollow cylindrical section and thestrips maintained in this relation by tongue and groove projections onthe edges of the individual strips or segments. This type of conductorhas the advantages of low corona discharge because of the large radiusof the outer surface and the smooth the electrical load combined into asingle element in which the two metals are substantially uniformly andintegrally bonded together all over their adjacent surfaces and one inwhich the metal of high conductivity has its thickness limited to thatwhich really serves to carry the alternating current transmittedtherethrough.

Referring to Figs. 1, 2 and 3, I have shown three forms out of manywhich my improved conductor may assume. In Fig. 1 I have shown an opencylindrical conductor which consists of an inner shell 2 of steel and anouter shell 3 oi copper. The conductor shown in this figure is an opencylinder having its adjacent edges slightly spaced from each other. InFig. 2 I have shown a similar conductor also formed of an inner stee1layer and an outer copper layer 3 formedin the shape of a substantialsquare and also having its edges slightly spaced from each other. InFig. 3 the form of the conductor is shown as being roughly diamondshaped with the open edges at one of the corners of the diamond and itwill be understood that the conductor may take various other forms asmay be desired.

The thickness of the inner supporting layer of steel and of'the outercarrying layer or copper will obviously depend upon the physical strainswhich will be imposed upon the conductor in one case and the magnitudeof the electric current which is to be transmitted in the other. In aconductor of approximately two inch diameter, the thickness of the innersteel layer will range from 40 to of inch and the thickness of thecopper layer from about 25 to 50% of the thickness .of the steel layer.-These proportions will be maintained regardless of the shapeof thecon-1 ductor. The composite strip may be formed in the first instance bythe method described in the co-pending application of George Edwards,Serial No. 246,127, now Patent 2,203,679 dated June 11, 1940, in whichthere is described a process of applying a molten layer of a metal oflower melting point than steel to a strip of metal such'as steel whichserves as a-backing and reinforcing element for the copper or metal oflower melting One of the advantages of the present conductor is that itmay beformed from the flat cornposite strip intqthe desired crosssectional shape economically and rapidly either in the factory or in theheld in the following manner:

present mittently and this may be done in any of the various forms ofconductors herein shown. 'In

Fig. 8, for example, I have shown the edges of the conductor of Fig. 1welded to each other to form a closed tubular conductor.

In Fig. 71 have shown a conductor consisting of a spirally woundbimetallic stripv of the character already described formed into asubstantialiy cylindrical element. This spiral strip may have theadjacent edges either continuously or intermittently joined and thewidth of the strip should be relatively high in proportion to thediameter of the strip to provide strength and rue composite strip whenfirst formed is coiled into a coil i0 having a length of several hundredor even several thousand feet. This coil may .then be mounted on asuitable shaft ii and the strip slowly unwound and drawn betweenrollers" 12 and i3 and thereby passed through a die M which may be ofany desired interior shape to I form the flat strip into the desiredhollow cross sectional shape, either of the type illustrated in Figs. l,2 and 3 or some'other form. This apparatus which is commonly employedin-the sh p to'form open or channel like tubing of various crosssections is inexpensive, rapid in operation 7 and entirely standard inconstruction. It lends.

itself readily to being mounted upon a truck or other movable platformwhich can be taken into the field where the composite strip can beformed intothedesired cross sectional shape as it is its currentcarrying-capacity and also to produce an extremely smooth outer surfaceon the .comv polite tube. By reason of the tubular form of theconductor,

the-strength of the steel core will prevent collapse. Fiexibilityof theentire element also strength and characteristics. of

secured rrom the 1 thesteel inner core.

a further advantage of the present conductor a is that it can bemanufactured 'in a relatively flexible condition, in which condition thecomtofu place ofuse. Afterbeinz formedinthe shown mm 4, Sand 6 into ahollow lindrical squareor other shaped tube, it

the usualloads and toresist the torsionalforcesresultingfromwindandrainwhichhave been known to give some troublevwith present v o! bedesirabletounitetheadiacenteglgesofthe tormedtubular which conductors. l'brsomepurposesitmayresistance to deformationsufficient to maintain the strip in the form shown.

The present invention provides a conductor in alternating currents whichis very much less expensive in its construction and much-more economicalin the' use of the more expensive metals contained therein than that ofthe conductor now employed in transmission lines;

Other modes of applying the principle of my invention may be employedinstead of the one explained, change being made as regards the structureherein disclosed, provided the means stated by any of the followingclaims or the equivalent of such stated means be employed. I thereforeparticularly point out claim as my invention:

and distinctly 1. A tubular conductor having a high capacity v forcarrying alternating currents comprising a strip of steel and a strip ofmetal of substantial thickness and of relatively high conductivitysuperimposed directly thereon against one side thereof and substantiallyintegrally and uniformly bonded directly thereto all over theircontacting surfaces, saidhigh conductivity metal lying on the outersurface of the tubular conduc- Q tor and havinga dense compactedstructure and smooth outer surface, resulting in a higher currentcarrying capacity.

2. A conductor having a capacity for carrying alternating currentscomprising abi-' .metallic tubular member of substantially-squarecrosssection having its edges closely adjacent but spaced from eachother and having an inner layer offsteeland an outer l yet of compactedpper,,resulting in higher current carrying cacitys 3. A conductor havinga high capacity lion carrying alternating currents comprising abimetallic tubular member of substantially cylindrical cross-sectionhaving its-edges united to each other and having an inner layer of steeland an outer layer of compacted coppe result-f,

wing in higher current carrying capacity. 5 I high capacity for' 41Aconductor having a carrying alternating currents. comprising a bistripcanbe coiled readily and transported becomes-very much more rigid whileA asufilcient flexibilityto permit. it to be hnmbetween the usualsupp'ortsandto and of relatively high conductivity on its outer surfaceand a layer of metal of high mumtes' die-rs metallic tubular memberconsisting of a bime-r tallic strip formed intoa spiral tube-like coil,one of the metals of said bimetallic strip being a compacted metal ofhigh conductivity and forming the outer surface of the conductor, saidcompacted metalresulting in a higher current carry n capa ty- 5. Aconductor. having a high capacity for alternating currents comprisinga'ccmposite; strip formed into a curved section, said strip consistingof a. layer of metal of substantial tensile strength on its innersurface, the two layers being substantially uniformly and directlyconductor either continuously or intersmooth outer surface, resulting ina higher current carrying capacity.

6. A conductor having-a high capacity for carrying alternating currentscomprising a com-- posite strip of steel and a strip of compactedaluminum superimposed thereon against one side thereof and substantiallyintegrally and uniform- 1y bonded thereto all over their contactingsurfaces.

7. A conductor having a high capacity for carrying alternating currentscomprising a bimetallic tubular member consisting of a bimetallic stripformed into a spiral tube-like coil with the adjacent edges of the stripjoined to each other, one of the metals of said bimetallic strip being acompacted metal of high conductivity and forming the outer surface ofthe conductor.

8. The method of making a bimetallic tubular conductor having a highcapacity for carrying alternating current which comprises providing astrip consisting of a layer of steel, applying a layer of substantialthickness of a metal of high conductivity to said steel strip andintegrally and uniformly bonding said applied metal to said steel stripall over their contacting surfaces, compacting said high conductivitymetal to provide a dense structure and a smooth outer surface, andforming said strip into a tubular member of which said high conductivitymetal forms the outer surface of the tubular conductor.

9. The method of making a bimetallic tubular conductor having a highcapacityefor carrying alternating current which comprises providing ,astrip consisting of alayer of steel, applying a layer of copper ofsubstantial thickness to said steel strip and bonding said copper layerto said steel strip integrally and uniformly all over their contactingsurfaces, compacting the copper layer said high conductivity metal formsthe to provide a dense structure and a smooth outer surface, and formingsaid strip into a tubular member of which said copper forms the outersurface of the tubular conductor.

10. The method of making a bimetallic tubular conductor having a highcapacity for carrying alternating current which comprises providing abimetallic strip consisting of a layer of steel and a layer of compactedaluminum of substantial thickness, said layers being integrally anduniformly bonded together all over their contacting surfaces, andforming said strip into a tubular member of which said aluminum formsthe outer surface.

11. The method of making a bimetallic tubular conductor having a highcapacity for carrying alternating current which comprises pouring moltenmetal having a high conductivity onto a moving backing strip of steel,thereby integrally and uniformly bonding said metal and strip togetherall over their contacting surfaces, rolling or compacting said highconductivity metal to density the structure thereof as well as toproduce a smooth outer surface thereof, and forming said strip into atubular member of which outer periphery of the tubular conductor.

12. The method of making a bimetallic tubular conductor having a highcapacity for carrying alternating current which comprises pouring moltencopper onto a moving backing strip of steel, thereby integrally anduniformly bonding the copper and steel together all over theircontacting surfaces, rolling or compacting the coppet to densify thestructure thereof as well as to produce a smooth surface thereon, andforming V said strip into a tubular member of which the copper forms theouter periphery of the tubular conductor. 1

CARL a. SWARTZ.

